I do see what you mean,
why not do this..
empty 2 liter, cut the bottom off, the cap that goes on the top, make a hole and get a brass pipe bowl, make a hole on the cap, bowl go with the cap.... then get clean bread bag.. (merta bread bag), or trash bag
clean the inside bag and 2 liter, then attach the bag to the bottle, tape it all around duct tape works good, then put cap with bowl back to the bottle s twist.. okay first step, get cap with bowl off, suck the bottle up till the bag is completly under the bottle... then put the cap back on along with bowl... fire it up, pull the bag out of the 2 liter, u gonna have huge smokes, then get cap off.. suck it, bang u down big time!! its simple process..